Authorities are beginning to get a clearer picture of the scale of destruction and say hundreds of homes have been lost across the state.

In the worst-hit areas in the Blue Mountains, the Rural Fire Service says 30 per cent of properties have been inspected, with 81 confirmed lost and 37 damaged.

More than 20 bushfires continue to burn uncontained across parts of the state as more than 2,000 firefighters, including interstate reinforcements, are involved in battling the blazes.

Prime Minister Tony Abbott has praised the efforts of fire crews: "These are ordinary people who, on an extraordinary day, come together to support their community and to protect their fellow Australians."